Image metadata is essentially non-picture information that is embedded in the image file in addition to the actual image data. Several industry groups and vendors have attempted to define image file formats to specify and support a baseline set of metadata to help promote widespread use of specific metadata by industry and consumers.
Metadata is typically associated with a digital image either at the time the digital image file is created, such as by a digital camera or scanner, or later added to the image by the user using an image editing application. Metadata provided by a digital camera or scanner is typically information about the image; the date and time the picture was taken, by whom, with what equipment, and the like. The data provided by the user are typically keywords, called tags, that are used to categorize the image for subsequent searching. Metadata entered by the user is typically in text format, but may also include audio annotations.
Metadata may be used to the advantage of both vendors and users. For example, metadata can help vendors render digital images with higher quality. A vendor that produces both digital cameras and printers, for instance, may use the metadata extracted from an image to send to a printer driver to allow the printer to enhance the print quality of the image. Users may use metadata to help better organize their images by sorting and searching based on metadata elements such as date and time, location, or keywords, for example. Users also use metadata to annotate images for sharing or for archiving.
For example, a user might take pictures at a sporting event using a digital camera, download the captured images to a PC, annotate the images using an image application, and then share the images with others via email or by posting the annotated images on a photosharing site. The other users might also further annotate the images. Finally, the user may copy the images to an optical drive, such as a DVD/CD or other type of external mass storage device, for archival. When images are archived, the images may be archived with metadata in the image file, or the metadata may be extracted and stored in a separate file or database.
Although image metadata may provide a host of benefits to vendors and users, as described above, the type of information stored as image metadata is typically limited to information describing the image capture process and characteristics of the image, and information entered by the user in the form of keywords and annotations. Consequently, when an image is displayed or archived, the information available for display or archival with the image is also limited to the information describing image capture process and characteristics of the image, and the metadata entered by the user.
There is a need, therefore, for automatic methods for associating external content, i.e., information originating outside of the image metadata, with a digital image when the image is displayed or archived. The present invention, as described below, meets this need.